We owe much thanks to Mullet for doing most of the BoM revision, associated parts subbing/etc. and building out the 1st of the new rev. For completeness:
GB for this: "Group buy for CTH" - http://www.head-fi.org/forum/thread/536098/closed-group-buy-for-cth-compact-tube-hybrid-pcb
Earlier "A Very Compact Hybrid Amp" spec & build thread - http://www.head-fi.org/forum/thread/398839/a-very-compact-hybrid-amp
> The only non-standard situation that I've run into is for the C13P and C14P film caps. I had to bend the leads outwards to fit them into position
This is because places were out of the 7.5mm pitch cap spec'd there so the rev'd BoM must have a 5mm pitch part #.
No biggie but we should note this in BoM comment or ID a better sub.
BTW Mouser seems to be out of common parts lately (e.g. many Wima films, some common BC transistors, and the "long" hammond cases until recently, etc.)
The changes in this new rev are largely ones that make building easier & should not result in sound or performance difference compared to proper earlier CTHs.
- Space to better fit C3H. Though new BoM 2026A+ 330uf part has better specs and 330uf has proved plenty to fix early CTH hum issues, a 470uf can be fitted there now at the builder's option.
- C1H, C2H increased to 150u taking advantage of a new series of caps (thanks to user rds).
- A TO225 (2N49922) Q1P that can handle much larger currents like cases where there is a short on the output of the regulator. Though the earlier re-spec'd BC337 has proven sufficient for expected loads, this change provides even more current "headroom".
- More room around C4L and C4R to give you more space to tombstone other caps in that area.
- More room to fit the heatsink on the 24V regulator.
- PCB support for up to 4 heater voltages. Base 12.6V & 6.3V plus up to two other voltages if you wish & provide a way to switch amongst them. This was accomplished through off-board resistors in the past, and you can still support as many heater Vs as you wish using that method.
- Misc organization tweaks WRT some diode positions, comp spacing, etc.
As Mullet indicated, runeight will update the CTH site with the various revision-related files & info once Mullet's build is proofed.
For the curious, here's the last PCB spec image I have from runeight:
Edited by cfcubed - 3/20/11 at 12:37pm